enum ChessStage {
  opening,
  early_middle_game,
  middle_game,
  late_middle_game,
  endgame,
}

/// 下棋所处的阶段
ChessStage chessStage(int count) {
  if (count >= 0 && count <= 30) {
    return ChessStage.opening;
  } else if (count > 30 && count <= 60) {
    return ChessStage.early_middle_game;
  } else if (count > 60 && count <= 110) {
    return ChessStage.middle_game;
  } else if (count > 110 && count <= 160) {
    return ChessStage.late_middle_game;
  } else {
    return ChessStage.endgame;
  }
}
